int
stress_majorization_with_hierarchy(
vtx_data* graph, /* Input graph in sparse representation */
int n, /* Number of nodes */
int nedges_graph, /* Number of edges */
double** d_coords, /* Coordinates of nodes (output layout) */
int dim, /* Dimemsionality of layout */
int smart_ini, /* smart initialization */
int model, /* difference model */
int maxi, /* max iterations */
double levels_gap
)
{
int iterations = 0; /* Output: number of iteration of the process */
/*************************************************
** Computation of full, dense, unrestricted k-D **
** stress minimization by majorization **
** This function imposes HIERARCHY CONSTRAINTS **
*************************************************/
int i,j,k;
bool directionalityExist = FALSE;
float * lap1 = NULL;
float * dist_accumulator = NULL;
float * tmp_coords = NULL;
float ** b = NULL;
#ifdef NONCORE
FILE * fp=NULL;
#endif
double * degrees = NULL;
float * lap2=NULL;
int lap_length;
float * f_storage=NULL;
float ** coords=NULL;
double conj_tol=tolerance_cg; /* tolerance of Conjugate Gradient */
float ** unpackedLap = NULL;
CMajEnv *cMajEnv = NULL;
clock_t start_time;
double y_0;
int length;
DistType diameter;
float * Dij=NULL;
/* to compensate noises, we never consider gaps smaller than 'abs_tol' */
double abs_tol=1e-2;
/* Additionally, we never consider gaps smaller than 'abs_tol'*<avg_gap> */
double relative_tol=levels_sep_tol;
int *ordering=NULL, *levels=NULL;
double hierarchy_spread;
float constant_term;
int count;
double degree;
int step;
float val;
double old_stress, new_stress;
bool converged;
int len;
int num_levels;
float *hierarchy_boundaries;
if (graph[0].edists!=NULL) {
for (i=0; i<n; i++) {
for (j=1; j<graph[i].nedges; j++) {
directionalityExist = directionalityExist || (graph[i].edists[j]!=0);
}
}
}
if (!directionalityExist) {
return stress_majorization_kD_mkernel(graph, n, nedges_graph, d_coords, dim, smart_ini, model, maxi);
}
/******************************************************************
** First, partition nodes into layers: These are our constraints **
******************************************************************/
if (smart_ini) {
double* x;
double* y;
if (dim>2) {
/* the dim==2 case is handled below */
stress_majorization_kD_mkernel(graph, n, nedges_graph, d_coords+1, dim-1, smart_ini, model, 15);
/* now copy the y-axis into the (dim-1)-axis */
for (i=0; i<n; i++) {
d_coords[dim-1][i] = d_coords[1][i];
}
}
x = d_coords[0]; y = d_coords[1];
compute_y_coords(graph, n, y, n);
hierarchy_spread = compute_hierarchy(graph, n, abs_tol, relative_tol, y, &ordering, &levels, &num_levels);
if (num_levels<=1) {
/* no hierarchy found, use faster algorithm */
return stress_majorization_kD_mkernel(graph, n, nedges_graph, d_coords, dim, smart_ini, model, maxi);
}
if (levels_gap>0) {
/* ensure that levels are separated in the initial layout */
double displacement = 0;
int stop;
for (i=0; i<num_levels; i++) {
displacement+=MAX((double)0,levels_gap-(y[ordering[levels[i]]]+displacement-y[ordering[levels[i]-1]]));
stop = i<num_levels-1 ? levels[i+1] : n;
for (j=levels[i]; j<stop; j++) {
y[ordering[j]] += displacement;
}
}
}
if (dim==2) {
IMDS_given_dim(graph, n, y, x, Epsilon);
}
}
else {
initLayout(graph, n, dim, d_coords);
hierarchy_spread = compute_hierarchy(graph, n, abs_tol, relative_tol, NULL, &ordering, &levels, &num_levels);
}
if (n == 1) return 0;
hierarchy_boundaries = N_GNEW(num_levels, float);
/****************************************************
** Compute the all-pairs-shortest-distances matrix **
****************************************************/
if (maxi==0)
return iterations;
if (model == MODEL_SUBSET) {
/* weight graph to separate high-degree nodes */
/* and perform slower Dijkstra-based computation */
if (Verbose)
fprintf(stderr, "Calculating subset model");
Dij = compute_apsp_artifical_weights_packed(graph, n);
} else if (model == MODEL_CIRCUIT) {
Dij = circuitModel(graph, n);
if (!Dij) {
agerr(AGWARN,
"graph is disconnected. Hence, the circuit model\n");
agerr(AGPREV,
"is undefined. Reverting to the shortest path model.\n");
}
}
if (!Dij) {
if (Verbose)
fprintf(stderr, "Calculating shortest paths");
Dij = compute_apsp_packed(graph, n);
}
diameter=-1;
length = n+n*(n-1)/2;
for (i=0; i<length; i++) {
if (Dij[i]>diameter) {
diameter = (int)Dij[i];
}
}
if (!smart_ini) {
/* for numerical stability, scale down layout */
/* No Jiggling, might conflict with constraints */
double max=1;
for (i=0; i<dim; i++) {
for (j=0; j<n; j++) {
if (fabs(d_coords[i][j])>max) {
max=fabs(d_coords[i][j]);
}
}
}
for (i=0; i<dim; i++) {
for (j=0; j<n; j++) {
d_coords[i][j]*=10/max;
}
}
}
if (levels_gap>0) {
int length = n+n*(n-1)/2;
double sum1, sum2, scale_ratio;
int count;
sum1=(float)(n*(n-1)/2);
sum2=0;
for (count=0, i=0; i<n-1; i++) {
count++; // skip self distance
for (j=i+1; j<n; j++,count++) {
sum2+=distance_kD(d_coords, dim, i, j)/Dij[count];
}
}
scale_ratio=sum2/sum1;
/* double scale_ratio=10; */
for (i=0; i<length; i++) {
Dij[i]*=(float)scale_ratio;
}
}
/**************************
** Layout initialization **
**************************/
for (i=0; i<dim; i++) {
orthog1(n, d_coords[i]);
}
/* for the y-coords, don't center them, but translate them so y[0]=0 */
y_0 = d_coords[1][0];
for (i=0; i<n; i++) {
d_coords[1][i] -= y_0;
}
coords = N_GNEW(dim, float*);
f_storage = N_GNEW(dim*n, float);
for (i=0; i<dim; i++) {
coords[i] = f_storage+i*n;
for (j=0; j<n; j++) {
coords[i][j] = (float)(d_coords[i][j]);
}
}
/* compute constant term in stress sum
* which is \sum_{i<j} w_{ij}d_{ij}^2
*/
constant_term=(float)(n*(n-1)/2);
/**************************
** Laplacian computation **
**************************/
lap2 = Dij;
lap_length = n+n*(n-1)/2;
square_vec(lap_length, lap2);
/* compute off-diagonal entries */
invert_vec(lap_length, lap2);
/* compute diagonal entries */
count=0;
degrees = N_GNEW(n, double);
set_vector_val(n, 0, degrees);
for (i=0; i<n-1; i++) {
degree=0;
count++; // skip main diag entry
for (j=1; j<n-i; j++,count++) {
val = lap2[count];
degree+=val; degrees[i+j]-=val;
}
degrees[i]-=degree;
}
for (step=n,count=0,i=0; i<n; i++,count+=step,step--) {
lap2[count]=(float)degrees[i];
}
#ifdef NONCORE
fpos_t pos;
if (n>max_nodes_in_mem) {
#define FILENAME "tmp_Dij$$$.bin"
fp = fopen(FILENAME, "wb");
fwrite(lap2, sizeof(float), lap_length, fp);
fclose(fp);
}
#endif
/*************************
** Layout optimization **
*************************/
b = N_GNEW (dim, float*);
b[0] = N_GNEW (dim*n, float);
for (k=1; k<dim; k++) {
b[k] = b[0]+k*n;
}
tmp_coords = N_GNEW(n, float);
dist_accumulator = N_GNEW(n, float);
#ifdef NONCORE
if (n<=max_nodes_in_mem) {
#endif
lap1 = N_GNEW(lap_length, float);
#ifdef NONCORE
}
int stress_majorization_cola(
vtx_data * graph, /* Input graph in sparse representation */
int n, /* Number of nodes */
int nedges_graph, /* Number of edges */
double **d_coords, /* Coordinates of nodes (output layout) */
node_t **nodes, /* Original nodes */
int dim, /* Dimemsionality of layout */
int model, /* difference model */
int maxi, /* max iterations */
ipsep_options * opt)
{
int iterations = 0; /* Output: number of iteration of the process */
/*************************************************
** Computation of full, dense, unrestricted k-D **
** stress minimization by majorization **
** This function imposes HIERARCHY CONSTRAINTS **
*************************************************/
int i, j, k;
float *lap1 = NULL;
float *dist_accumulator = NULL;
float *tmp_coords = NULL;
float **b = NULL;
double *degrees = NULL;
float *lap2 = NULL;
int lap_length;
float *f_storage = NULL;
float **coords = NULL;
int orig_n = n;
/*double conj_tol=tolerance_cg; *//* tolerance of Conjugate Gradient */
CMajEnvVPSC *cMajEnvHor = NULL;
CMajEnvVPSC *cMajEnvVrt = NULL;
double y_0;
int length;
DistType diameter;
float *Dij = NULL;
float constant_term;
int count;
double degree;
int step;
float val;
double old_stress, new_stress = 0;
boolean converged;
int len;
double nsizeScale = 0;
float maxEdgeLen = 0;
double max = 1;
initLayout(graph, n, dim, d_coords, nodes);
if (n == 1)
return 0;
for (i = 0; i < n; i++) {
for (j = 1; j < graph[i].nedges; j++) {
maxEdgeLen = MAX(graph[i].ewgts[j], maxEdgeLen);
}
}
/****************************************************
** Compute the all-pairs-shortest-distances matrix **
****************************************************/
if (maxi == 0)
return iterations;
if (Verbose)
start_timer();
if (model == MODEL_SUBSET) {
/* weight graph to separate high-degree nodes */
/* and perform slower Dijkstra-based computation */
if (Verbose)
fprintf(stderr, "Calculating subset model");
Dij = compute_apsp_artifical_weights_packed(graph, n);
} else if (model == MODEL_CIRCUIT) {
Dij = circuitModel(graph, n);
if (!Dij) {
agerr(AGWARN,
"graph is disconnected. Hence, the circuit model\n");
agerr(AGPREV,
"is undefined. Reverting to the shortest path model.\n");
}
} else if (model == MODEL_MDS) {
if (Verbose)
fprintf(stderr, "Calculating MDS model");
Dij = mdsModel(graph, n);
}
if (!Dij) {
if (Verbose)
fprintf(stderr, "Calculating shortest paths");
Dij = compute_apsp_packed(graph, n);
}
if (Verbose) {
fprintf(stderr, ": %.2f sec\n", elapsed_sec());
fprintf(stderr, "Setting initial positions");
start_timer();
}
diameter = -1;
length = n + n * (n - 1) / 2;
for (i = 0; i < length; i++) {
if (Dij[i] > diameter) {
diameter = (int) Dij[i];
}
}
/* for numerical stability, scale down layout */
/* No Jiggling, might conflict with constraints */
for (i = 0; i < dim; i++) {
for (j = 0; j < n; j++) {
if (fabs(d_coords[i][j]) > max) {
max = fabs(d_coords[i][j]);
}
}
}
for (i = 0; i < dim; i++) {
for (j = 0; j < n; j++) {
d_coords[i][j] *= 10 / max;
}
}
/**************************
** Layout initialization **
**************************/
for (i = 0; i < dim; i++) {
orthog1(n, d_coords[i]);
}
/* for the y-coords, don't center them, but translate them so y[0]=0 */
y_0 = d_coords[1][0];
for (i = 0; i < n; i++) {
d_coords[1][i] -= y_0;
}
if (Verbose) fprintf(stderr, ": %.2f sec", elapsed_sec());
/**************************
** Laplacian computation **
**************************/
lap2 = Dij;
lap_length = n + n * (n - 1) / 2;
square_vec(lap_length, lap2);
/* compute off-diagonal entries */
invert_vec(lap_length, lap2);
if (opt->clusters->nclusters > 0) {
int nn = n + opt->clusters->nclusters * 2;
int clap_length = nn + nn * (nn - 1) / 2;
float *clap = N_GNEW(clap_length, float);
int c0, c1;
float v;
c0 = c1 = 0;
for (i = 0; i < nn; i++) {
for (j = 0; j < nn - i; j++) {
if (i < n && j < n - i) {
v = lap2[c0++];
} else {
/* v=j==1?i%2:0; */
if (j == 1 && i % 2 == 1) {
v = maxEdgeLen;
v *= v;
if (v > 0.01) {
v = 1.0 / v;
}
} else
v = 0;
}
clap[c1++] = v;
}
}
free(lap2);
lap2 = clap;
n = nn;
lap_length = clap_length;
}
